Unzipped Composites

Sure, but if it's a wank factor thing then there's plenty of other stuff there that they could have done - fuse box cover, washer bottle, rad shroud, etc. Strut towers are an odd place to start, especially considering it isn't really a bang up job either, it's a little bit rough compared to how gorgeous the rest of the car is. I'm sure they had a reason, it just isn't obvious to me and I'd love to know what the Nismo designers were thinking with it.

As long as you have the push/pull variant correct.

Would really love to know their reasoning for wrapping the strut towers in carbon. It's doing nothing for strength/rigidity, so I feel it can only be a looks thing... but thats an odd place to start doing stuff in carbon.

Yeh unfortunately you'll never get a great surface finish using PVA release agent. It forms it's own surface, and even sprayed, it will get bits of dust in it and not lay down flat etc. It has it's uses, but I use it very rarely these days. Semi-permanent chemical release agents are the way to go. There's no reason your current mould can't work for carbon. The biggest issue would be whether you have used a polyester or vinyl ester tooling gelcoat, as you would want to use epoxy to make your carbon component and epoxy isn't compatible with polyester, it will stick to it. If you've used polyester, then to use your current mould you would need to spray PVA release agent in order to build up a nice thick film with absolutely no fish eyes or porosity where the epoxy can come into direct contact with the mould surface. For that reason, I wouldn't bother trying to sort out the surface finish on your current mould. I assume you'll be painting the fibreglass bodywork, in which case that will sort out the finish on that, and if you do end up using it for carbon then you'll have to use PVA anyway and then clear coating the carbon will be the best way to get a decent surface finish on that. In all honesty though, I wouldn't bother with trying to wet-lay carbon. You really need vacuum to get good consolidation and get full advantage of the strength to weight, and if you've got the equipment for vacuum then you may as well be infusing to really get a perfect result straight from the mould. To infuse, your current mould may be a bit troublesome. The flanges are quite small, so you will struggle to position your consumables and get a good seal, which is critical. Really need a 5" flange for infusion. Then with infusion as I mentioned above, you can get a perfect surface finish straight from the mould - so then you would want your mould surface to be vinyl ester and have the surface finish you want so that you can use a chemical release agent. Carbon layup could be quite a bit lighter than the fibreglass layup. On the bonnet section I would do a single layer of 200g twill, a 2mm core, and then another layer of the 200g twill. The fenders and front bumper sections don't need the core, they could be a single layer of 200g and a single layer of 450g and that would be plenty strong enough. Extra reinforcement around the mounting points again and you're dusted. With infusion, you should be able to get the total weight of the entire front end down to about 4-5kg. If you get the chance, definitely come over for one of my courses. It's a great 4 days, bunch of fun, you'll learn way more than anyone can handle, and it's worth it just for the lunches ? haha seriously though, if you're interested let me know. For my interstate guys I try to do 4 days in a row rather than splitting it over two weekends. You lose a bit of the course content because there isn't enough time to post cure the moulds you make to use them with pre-preg, so I have to supply some moulds for that part of it, but it saves you spending a week over here.

Go with what Soric specify in their data sheet. I actually meant 550g per m2 per mm thickness, so that's about right. But I couldn't remember exact numbers, it's been awhile since I used Coremat. 1kg per m2 for 2mm thick Coremat seems right. Resin ratio for wet layup of woven, unidirectional or stitched (double bias is a stitched material) is 1:1. So for a 400g DB, you will need 400g of resin per square metre per layer. Your layup schedule sounds good. Make sure you add an extra couple layers of the double bias in the areas where the bodywork is going to be mounted to spread those loads. Also if you are going to use bonnet pins, leave the core out of those areas and do extra double bias. Cores don't like compressive loads, so better to make those areas solid fibreglass. Happy to help man, that's what forums are for! Looking forward to seeing you nail this layup, then later I'll talk you into redoing it in carbon ?

I had 182/3 across all 6 when I comp tested a few years ago. Done some k's since then, should get the comp tester out again and see how she's feeling these days!

Excellent. Keep in mind with the pigment, you don't want to add too much. White gelcoat is already pigmented, and you ideally don't want to go over 10% total pigment or you may have cure issues. You can add a bit of the blue to get a very light blue tinge, but I wouldn't add more than 5% by weight in case they had a lot of the white pigment in there to begin with. No issue replacing the twill with the CSM, it wont have much of an effect on weight. In that case, I would do the layup similar to the method you used to make your mould, a layer of the 100g CSM as a single skin making sure to get all the air voids out, and let that cure for a couple of hours before doing the biaxial. That will reduce your print through, and reinforce the gelcoat. Then you can use the biaxial to give the laminate it's strength, and it won't matter as much if you get a bit of bridging as the gelcoat will still have some reinforcement behind it. Alternatively, you don't necessarily need twill fibreglass, you could get a plain weave instead. Will just need more relief cuts to go around corners. Foam brushes are fine, they can be a bit easier to use with woven materials than bristle brushes. Not going to notice much difference working with CSM or biaxial. To be honest, on a job this size I would probably use a 5" short-napp roller (same as the fabric rollers you would use to paint a house) for the bulk work, and a 2" bristle brush for the tighter areas where the roller is too much work. That will let you get resin on the job and wet out the fibres quickly. Then use a disc roller to consolidate each layer and get the air bubbles out.

Yeh most of the cars I work with are PDM, they're very good. I just can't quite stretch the budget there yet, this is already turning into one of those 'oh shit I got a bit excited' parts of the cars life ? And hopefully I'll have a bit more composites chat coming soon! As much as I enjoy talking turbos and 'Milspec' wiring - composites are my field and what will set this build apart!

Yeh they are continuous fibres, so they won't break down like CSM. Harder to work with, but what you want to do is get all your fibreglass ready before you mix any resin or even apply the PVA. Lay the glass into the mould, and try to push it into all the corners as tight as you can. Take note of where it tries to 'bridge' the corners as you push it into place. If the fibres won't move to let you get them into place, then cut the fibres where they bridge to give it some relief and let it sit in place. Then use strips of glass with about an inch overlap either side to reinforce the cut sections. Make sure you do all of your glass and have it all ready before starting the layup, you don't want to be messing around with any of that while your resin is going off. Kind of like what I was doing here, you want to get all of the protrusions and features covered in glass with no bridging, and then lay up the bigger sections with the protusions cut out of it, if you know what I mean? For fibreglass with a gelcoat, it's not a huge issue to cut strips of material to reinforce tight areas, and put relief cuts where you need them. Then just add a bit of extra material to make up for the loss of strength where the cuts are.

You'll get there man, better not to rush these things - composites are unforgiving when you get it wrong! The PVA might still be ok by the time your gelcoat arrives if you keep it dry, although it may dry out a bit much and pre-release. I would probably wash it off now and let the mould dry off in the mean time.

Yeh that's gone... Sucks man, I know the feels I wouldn't use tooling gelcoat though. Cost aside, it is also more brittle than regular gelcoat, as it's supposed to be used on moulds with very little flex. Using it on a part that is going to have some flex, it will crack in no time. I mean if you really wanted to get it done, there's no reason you can't use it, it will work. But expect it to crack and chip quite quickly.

Yeh Trojan are great, I get some stuff from them too. When you do your gelcoat, you should be using about 650g per square metre. So if you roughly measure how much surface area you have, then you can calculate how much gelcoat you should be using to coat that area at correct thickness. If you get the area coated and you still have half a kg of gelcoat left, then you know you've left some areas a bit thin. If you're using CSM, it's going to be heavy, and then it actually needs to be stronger to support it's own weight, meaning it needs to be heavier again. Have you considered using woven/biaxial fibreglass instead? Will be significantly lighter and stronger than the chopped strand, and by using less resin you may find that it doesn't cost much more to do either. For example, if you were doing it that way I would do: 1 layer of 300g twill fibreglass > 1 layer of 450g double-bias fibreglass > 2mm Coremat (only in the flatter areas, leave it out of the contoured areas) > 1 layer of 450g double-bias > 1 layer of 300g twill. Plus an extra layer of the 450g DB in the areas with no core and the mounting points. That layup would need roughly 1.5kg of resin per square metre of glass, plus about 550g per square metre of Coremat, and I'd expect it to weigh about 4.5kg per square metre. An R34 front end is roughly what, 5.5sqm? That means you would need roughly 12kg of resin, 10kg of fibreglass, and end up with a front end weighing roughly 25kg once you factor in gelcoat. I'm not sure what you're paying for materials, but using average figures, I'd estimate you're looking at about $100 in resin and $300 in fibreglass. If you compare that to chopped strand, I would suggest the layup you mentioned is too light and wouldn't be strong enough to stand up to racing. I would be doing a minimum layup of: 1 layer 225g CSM > 1 layer 450g CSM > 2mm Coremat (again only on the flatter areas, let the geometry do the work for you) > 1 layer 450g > 1 layer 225g. Extra couple of layers of the 225g in the areas with no core, and an extra couple layers of the 450g in the mounting areas. Then chop strand really does like a 2:1 resin:fibre ratio, otherwise it is a bit too lean and the matrix doesn't take the load well (meaning it will crack and break easily). You could try to aim for your 1.5:1 ratio, but I would stick to 2:1 for longevity. Over a 5.5sqm area, this means you will need roughly 17kg of resin just for the glass, plus about 2.5kg for the Coremat, so about 20kg of resin all up. With about 10kg of fibreglass in there, plus the Coremat and the gelcoat, you're going to be up around 35-40kg total weight. Given the chopped strand is only going to cost you maybe $70 or so, but you're going to need twice the resin, so that's about $200 in resin. So you're 10-15kg heavier, and only saving a bit over $100. Not sure if that is helpful or just confusing haha.

Where are you getting your tooling gelcoat from, do you know if it is brush viscosity or spray viscosity? When you're brushing gelcoat, you really want to just slap it on virtually as thick as you can get it. Watch for pooling in the corners, but you're unlikely to make it too thick on flat sections. Good rule of thumb is if you can no longer see the colour of the pattern or flanges through the gelcoat, then you're probably close. Mould turned out well though! Are you planning on infusing or wet-laying the component?

Yeh full rewire. I'm not going to PDM though, just going to simplify and reorganise the fuses and relays. PDM's are great, but just not quite a priority yet. One day when I've had enough of fuses and relays, I'll redo it with a PDM. Gotta leave myself something to do in the future

I believe the proportioning is built into the body of the MC, rather than anything to do with it's operating components. In any case, I feel the OEM brake bias on a car that is far from OEM isn't necessarily the best situation anyway. I don't know much about these things, but I've got Evo 9 Brembo calipers up front with factory Z32 calipers in the back, so I feel like a bit more rear bias won't hurt.

Sent them an email yesterday about it, they got back to me straight away. Said they were aware of the no fluid to rear caliper issue at the time, and it has been rectified years ago with a redesign. Also confirmed their BM57 is based on a Z32, and so may have more rear bias than a Skyline BM57 - whether this is actually an issue will depend on the setup of the individual car it's on. Seem like a good company, so I'm happy to give it a go and report back. It can often be hard to shake a poor reputation through word of mouth once you've had an issue, but if they have identified problems and worked on them then that's all we can ask. If it works now, then it is a great solution for ABS and Non-ABS setups, and at a great price to boot.

Little bit of progress over the weekend, the interior has now been stripped out, just need to find the time to take care of the sound deadening (shudder) and gut the unnecessary stuff from the dash/doors/etc. Don't let anyone tell you otherwise, race cars pay for themselves All of the aircon gear has also been deleted, which was initially a bit hard to stomach for me... ABS is also gone Still need to get rid of the heater box from under the dash, but will wait to drain the coolant first. It's amazing how much room just the aircon and ABS takes up in the engine bay, it's already significantly neater in there. I also decided I wasn't going to mess around with the OEM wiring harness anymore, and it's time for a full motorsport spec harness for the car. OEM engine harness is out Absolute reliability is my goal, as I've seen enough motorsport to know that electrical issues can be one of the most expensive parts of having a race car. Making my own harness has been a long-term dream of mine, so I'm looking forward to the challenge. I also need the wiring to be capable of evolving with the setup as I develop the car; because I plan on using it to develop performance aero products I want to be able to log as much data as I can in relation to those products. I am already developing some laser ride height sensors in order to log downforce, and in the future I would like to be able to run additional sensors for things like pre-radiator temps for oil/water/air etc in order to work out how well my ducting is performing. While I'm at it, I've decided to convert to DBW throttle as well, to save having to modify that part of the harness later. All of this means that I am running out of AVI's on the ECU quite quickly. If I wired everything direct to the ECU, I would already have used all 16 AVI's with just the current sensors, 4 laser ride height sensors, and the DBW. The MXS Strada dash has 8 AVI inputs that I can make use of, but unfortunately doesn't have logging capabilities, and it is a bit hard to stomach the $1700 for the logging kit from AIM at the moment. So as an interim, I have setup the ECU and the dash on the bench, and am trying to workout how I can wire the non-critical sensors like ride height into the dash, and then stream that data to the Thunder via CAN in order to log it. Seems like such a simple idea, both units are able to transmit and receive CAN data, and the CAN channel is a loggable channel in the ECU. In practice, it's quite a lot of dicking around. AIM haven't made this dash very user friendly, so it isn't quite as straight forward as "receive this, transmit that". I may end up having to write a custom CAN protocol in order to get it to work the way I want, but the initial results seem to indicate that it can be done. This will free up a few AVI's on the ECU for future expansion. Next up, I've decided to pull the motor out. It's been 8 years since the motor was last out, and I'm looking forward to sorting out the things I did wrong back then, as well as cleaning up the engine bay again, probably weld up some unnecessary holes in the firewall, and making it a lot easier to route the new harness when it's done.

Interesting, that is obviously a bigger issue. Did you take it up with HFM, did they help at all?

If that is the only issue, then it isn't exactly an issue and more just something to be aware of and have in your mind if you get rear brake lock ups. Realistically, there's no saying standard distribution is more suited to a car than more rear bias. There's so many things affecting that, so standard bias on a modified S-chassis isn't necessarily the best anyway. I would consider leaking and poor fitment as issues to beware of, but I shall endeavour to report back on this once the car hits the track again. If it's not poor quality, then it may still be a very good cheap option.

I searched around and saw a few posts to this extent, but it was always reference to having read bad things, I never actually found a post written by someone who had a bad experience and what the issues were. There's a few good reviews on their website, not that those carry a lot of weight. We'll find out anyway, I've ordered one for my car. Figured it was worth a punt.

HFM sell a BM57 master cylinder for around $150. At that price, how could you not?

Pics and stuff:

Doing well mate! Not a small job, and certainly not an easy job to flange so nice work. Not sure if professional advice is welcome, but I can see you're getting a bit of alligatoring in places, just make sure you are applying the gelcoat thick enough (needs to be 0.7-0.8mm thick minimum), catalysing high enough (2% minimum for gelcoat, mix smaller batches if you don't have enough pot-life), and leaving it to cure for long enough before doing the coupling coat; I like to leave gelcoat overnight, longer if it is colder. It is air inhibited so you can leave it up to 24 hours without issue. Alligatoring causes all sorts of problems later especially if you are planning on infusing, trying to get a good seal on your bagging tape can be a real nightmare. Also just be careful with where you put your backing structure, these tend to print-through onto the surface of the mould over time and cause defects. If you'd like any advice with anything, feel free to PM me, I'm happy to share the knowledge. Otherwise also feel free to tell me to piss off and leave you to it!

Business Name: Unzipped Composites Business shop address: Unit 7/49 Conquest Way, Wangara, WA, 6065 Business shipping address: As above Business website URL: www.unzippedcomposites.com.au Business contact number: 04310 470 984 Business contact email: [email protected] Returns policy: Change of Mind Returns - None. All our products are made to order, and we do not accept returns for change of mind. Faulty Goods Returns: In the event of a manufacturing fault, we will offer a full replacement of the product. Please keep in mind that composite components are hand manufactured products, and small imperfections (such as pinholes, tiny scratches, trimming inconsistencies, etc.) can occur. We do not consider these to be manufacturing faults, but would be happy to work with customers on a case by case basis to ensure your satisfaction. Quality Guarantee: We want you to be over the moon with any products we make for you. We utilise Aerospace standard manufacturing processes and materials in order to provide you with composite components that wouldn't be out of place on an F1 car. On rare occasions, some blemishes may slip by unnoticed. In the event that you are dissatisfied with our service, please contact us so we can rectify any issues.

Hey guys, As I mentioned in my thread in the Newbie Intro section, I'm back on the forum with a new account and username. Used to spend a lot of time on here years ago as Hanaldo, so some of you may remember me and my car. The old build thread is here: That thread essentially covers everything I did to the car while it was my daily for 12 years. In September last year I got yellow stickered, and that was the end of that! I want to write this build thread to cover it's new life as a motorsport development car for my business (I will try to do that without breaking any forum rules). It is unfortunately going to be a slow build I think, I don't have a lot of time to work on the car these days, nor a significant budget for it. But hopefully once the Covid restrictions are lifted and we can get back out on the track, I can start to post some results and do some development. Power-wise, the last time it was on a dyno the car made 419rwhp @22psi on E85. There was plenty more in it, but it was suffering badly from ignition break-down at higher boost levels, and was just about on the limit that the clutch could handle. I bought an R35 GTR coil kit from Platinum Racing Products to take care of the ignition, and while upgrading the clutch to an NPC cushion button I also discovered that every single nut on the exhaust manifold was hand-tight and the gasket was blown - had probably been that way for months if not years. So we replaced that, along with the studs and nuts. While that was all underway, I decided I'd had enough of the old Link G4 plug-in, and decided to go all out with a G4+ Thunder and an MXS Strada dash. Unfortunately since wiring in the Thunder, we haven't had an opportunity to get the car back on the dyno for a tune, so that is about where things stand currently, but I am hoping to be up around the 480rwhp mark if not maybe sneak into the 500's. We will see, it is a factory bottom-end at the end of the day so I don't want to push it too far, and I'll be happy with where it ends up for a bit. I don't plan to build the motor anytime soon unless it breaks with a bit of track use, but it's always nice to know what it can do. Ultimately the car will be aimed at Time Attack, built to compete in Tuner Class in WA Time Attack (the same regulations as Clubsprint in WTAC). I decided to build it for this category, as I am actually already sponsoring a car being built for Racer (Open) Class and investing heavily in that, so I wanted to do something different with my car and not be in direct competition with something I certainly can't compete with! Tuner Class also appeals to me for the challenge of developing the aero to perform in what is really a non-aero class. It is quite 'easy' to develop aero components for cars competing in Open Class as the regulations allow so much more, but in Clubsprint the regulations on aero are quite restrictive and will require a bit of ingenuity to get the performance out of it. I will be doing the CAD and CFD in-house, but my intention is to use the Thunder to get creative with data logging, so hopefully I can back up any lap-time progress/regress with data to show what is working and what isn't. CFD is nice, but real-world data is king! That's about it for now, I will upload a few pictures soon and start taking more photos of anything that goes into the car so hopefully I'm not just posting walls of text!